The present invention relates to solar heat collectors and more particularly to such heat collectors wherein metallic nodular or dendritic surfaces are employed to increase the absorbtion effectiveness of the collector.
U.S. Pat. No. 3,920,413 discloses a panel for absorbing solar energy comprising an aluminum substrate coated with bright nickel with an overcoat of black nickel.
An article in Machine Design, Apr. 3, 1975, at page 24 discloses a dendritic solar energy absorber made by vapor depositing tungsten on a substrate. It is stated that better than 96% of light from the solar spectrum is captured by the tungsten dendrite array.